Chapter 5 The Muscular System The three major categories of muscle fibers are Skeletal Smooth Cardiac Muscle Tissue Skeletal Muscle striated voluntary muscle Attached to bones and are largely ID: 779208
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Slide1
Slide2Lesson 5.1
Muscle Tissue Categories and Functions
Chapter 5: The Muscular System
Slide3The three major categories of muscle fibers are:Skeletal Smooth
Cardiac Muscle Tissue
Slide4Skeletal Muscle (striated / voluntary muscle)Attached
to bones and are largely responsible for body movements.This type of muscle is
stimulated
by consciously directed
nerve activity
These muscle fibers (cells) have many nucleiThe number of muscle fibers in a given person is genetically determined and does not change as we age, except for loss in fibers due to injury.
Muscle Tissue Categories
Slide5Muscle fibers can increase in length and in diameter as we grow.
Adults can increase their fiber diameter, and strength, by resistance training with just a few repetitions of heavy loads on a regular basis over a period of time
Slide6Microscopic View of Striated Muscle
Slide7Smooth muscle (visceral muscles)These are small, spindle-shaped, nonstriated
and involuntary (not under conscious control)Found in the walls of many internal organs
Ex. The
stomach
,
intestines, blood vessels etc. Muscle Tissue Categories
Slide8Responsible for the propulsion of food in a wave-like motion down the
digestive tract in a process called peristalsisPeristalsisCan sustain long periods of contraction without getting fatigued
Slide9Microscopic View of Smooth Muscle
Slide10Cardiac MuscleIs located solely in the
walls of the heart.These muscle cells are branched
,
cross-striated
, and
involuntary—under the control of the autonomic nervous systemMuscle Tissue Categories
Slide11They have a distinguishing structure called intercalated disks which join spiral shaped bundles of muscle. This
enables simultaneous contraction of neighboring cells to produce the heartbeat.HeartbeatsHeart Anatomy
Slide12Microscopic View of Cardiac Muscle
Slide13Side by Side Comparison
Slide14Skeletal Muscle Organization
Slide15True or False?1. Smooth muscle is voluntary.
2. Cardiac muscle has branching fibers.3. Smooth muscle is multinucleate.Review and Assessment
False
True
False
Slide16All muscle tissues have four behavioral characteristics in common:Extensibility – the ability to be
stretchedElasticity – the ability to snap back to normal length after a stretch
Irritability
– the ability to
respond to stimulus
from the nervous system.Contractility – the ability to shorten or contract.
Behavioral Properties of Muscle
Slide17When a skeletal muscle develops tension, one of three actions can happen, the muscle can:
Shorten (concentric contraction)Remain the same length (
Isometric contraction
)
Lengthen (
eccentric contraction)Muscle Tissue Functions
Slide18Tension and types of skeletal muscle contractionAgonist (prime mover) – moves bone
Antagonist – opposes the movement of the agonist Muscle Tissue Functions, cont.
Slide19Shortening contraction of the biceps.Agonist contracts, antagonist relaxes
Concentric Contraction
Slide20Lengthening contraction of the biceps.Agonist contracts while lengthening, antagonist relaxes
Eccentric Contraction
Slide21Contraction of both biceps and triceps.No change in muscle length occurs.
Both agonist and antagonist contract.Isometric Contraction
Slide22Match these words with 1–5 below:
extensibility, elasticity, irritability,
contractility
,
agonist
, antagonist.1. Respond 2. Opposes movement3. Stretch
4. Shorten 5. Causes movement
Review and Assessment
Irritability
Antagonist
Extensibility
Contractility
Agonist
Slide23Lesson 5.2
Skeletal Muscle Actions
Chapter 5: The Muscular System
Slide24Muscle tissue is not able to develop tension unless stimulated by one or more
nerves.A nerve that stimulates skeletal muscle, which is under voluntary control, is known as a motor neuron.
A
motor unit
is a group of
muscle fibers under the control of one motor neuronThe Motor Unit
Slide25Sarcomeres are units that shorten by actin filaments sliding along myosin filaments
within the muscle fiber.Glucose stored within the muscle cell provides the energy for this contraction.
Contraction of the Sarcomeres
Slide26A signal (action potential
) always causes entire motor unit muscle fibers to contract.This is the all-or-none law, after which the muscle fiber returns to its resting state.
Muscle Action
Maximum Tension and Return to Relaxation
Slide27Skeletal muscle fibers may be divided into two umbrella categories:
Slow – twitch (type I) fibers contract slowlyFast – twitch (type II) fibers contract fastType
IIa
Type
IIb
Fast Twitch vs Slow TwitchThe fast- twitch/slow-twitch ratio varies from muscle to muscle and from person to person
Skeletal Muscle Fiber Types
Slide28Parallel fiber arrangementsFusiform
Bundled Triangular Pennate fiber arrangementsUnipennate
Bipennate
Multipennate
Skeletal Muscle Fiber Architecture (pattern)
Slide29Rotary force (force causing bone movement
) that muscles can produce at a jointThe maximum weight you can lift is a measurement of
muscular strength
Force x velocity
How
fast you can sprint is a measurement of muscle powerMuscular Strength
Slide30Muscle tension/timeHow
far you can run over a period of time is a measurement of muscle endurance
Muscle Endurance
Slide31Match these words with 1–5 below:
muscle endurance, muscular strength, muscle power,
Type I
,
Type II
. 1. Force x velocity2. Muscle tension/time3. Rotary force that muscles can produce at a joint4. Slow twitch, slow fatigue
5. Fast twitch, fast fatigue
Review and Assessment
Power
Type I
Type II
Muscle endurance
Muscle strength
On the Test!!
Slide32Lesson 5.3
The Major Skeletal Muscles
Chapter 5: The Muscular System
Slide33Skeletal muscles attach at either end of the muscle:
Origin The end of the muscle that attaches to a relatively fixed structure.
Insertion
The end of the muscle that
attaches
to a bone that typically moves when the muscle contracts.When stimulated to develop tension,
muscles can only pull. They are
incapable of pushing
.
Skeletal Muscle Attachments
Slide34To describe the human body and its movements, we refer to three major planes that pass through the center of the body:
Sagittal plane: forward and backward motionsFrontal plane: sideways movements
Transverse plane
: rotational movements
Skeletal Muscle Attachments
Slide35Slide36Flexion Extension Hyperextension
Dorsiflexion Plantar flexion Sagittal Plane Movements
Slide37Sagittal Plane Movements
Slide38Abduction Adduction Inversion Eversion
Radial deviationUlnar deviationFrontal Plane Movements
Slide39Medial rotationLateral rotationPronation
Supination Transverse Plane Movements
Slide40Circumduction Opposition
Multiplanar Movements
Slide41True or False?1. Circumduction is a multiple plane movement.
2. Supination is a multiple plane movement.3. The insertion is the fixed end of a muscle.4. Extension is a sagittal plane movement.
5. Adduction is a frontal plane movement.
Review and Assessment
True
False
False
True
True
Slide42Head and Neck Muscles
Slide43Trunk Muscles
Slide44Upper Limb Muscles
Slide45Lower Limb Muscles
Slide46Match these words with 1–4 below: head, trunk, upper limb, lower limb.
1. temporalis2. brachioradialis3. external oblique
4. biceps
femoris
Review and Assessment
Slide47Lesson 5.4
Common Injuries and Disorders of Muscles
Chapter 5: The Muscular System
Slide48Strain
This happens when a muscle is overstretchedIndividuals with a large degree of flexibility at particular joints are at a lower riskStrains are classified as:
Grade I (
mild
): tightness in the muscle
Grade II (moderate): pain cause by partial tearGrade III (severe): tearing of muscle, loss of function & internal bleeding and swelling
Muscle Injuries
Slide49Hamstring strains are frequent for athletes. Slow to heal
Tend to recur within the 1st year of returning to the sport
Slide50Contusion This is a
bruise or bleeding within the muscle resulting from an impact.
Myositis
ossificans
is a more serious condition due to repeated injury.Cramps These involve moderate to severe muscle spasms
that cause painCauses are generally unknown, but may include
electrolyte imbalance
and
dehydration
Muscle Injuries
Slide51Delayed onset muscle soreness (DOMS
)Typically occurs 24 – 72 hrs. after an unaccustomed activityThis involves
multiple microscopic tears in muscle tissue
causing
inflammation
, pain, swelling and stiffness
Muscle Injuries
Slide52Tendons are tough fibrous connective tissues that connect muscle to bones
Tendinitis is the inflammation of a tendon accompanied by pain and swellingTendinosis
results when tendinitis remains untreated resulting in
degeneration of the tendon
and eventual raptureTendon Injuries
Val Thoermer/Shutterstock.com
Slide53Rotational injury at shoulderSwimmers shoulder
Overuse of elbowTennis elbowShin splintsPain localized to the medial lower leg.
Whiplash
Injury to the neck common as a result of automobile accidents resulting from an abnormal motion of the cervical vertebrae.
Joint Injuries
Slide54Muscular dystrophyThis is a group of similar,
inherited disorders characterized by progressively worsening muscle weakness and loss of muscle tissue
.
There are
no known cures
Treatments are to control symptomsMuscle Disorders
Slide55Hernia This is a
balloon-like section of the abdominal cavity lining that protrudes through a hole or weakened section of the muscles in the abdomen.May be caused by heavy lifting,
increased pressure inside abdominal cavity
or
no specific cause.
Muscle Disorders, cont.
Slide56True or False?1. Tendinitis is muscle strain.
2. A contusion is a bruise.3. Whiplash is a joint injury.4. A hernia is a tendon injury.5. A strain is an over stretch of a tendon.
Review and Assessment
False
True
True
False
False